Re: Jacaranda right along the coast

Nan,
I should have qualified my advice on Jacaranda
plantings within immediate coastal influence...  There
is a world of difference between San Diego and
northern California conditions, and it is obvious that
here in northern California the onshore winds are much
colder, stronger and more consistent, and not to the
liking of Jacaranda.  I remember working on a project
located in Santa Monica, and the city arborist was
adamant that Jacaranda was not a good choice for the
coastal bluffs right at the beach, even though some
could be seen blooming under such conditions.  It was
also obvious that just a few blocks further in from
the beach Jacaranda did grow and bloom well.  It is
also probable that the Jacarandas in Santa Monica's
Fourth Street Mall will never get as large or bloom as
heavily as those just a few miles further inland.

The point to be made is that they do best where they
get more heat and less cold wind off the ocean, which
is much more typical here in northern California. 
Even right along the coast, in winter our lows go
below 40F, and summer lows average right around 55F, a
good 5 to 10F colder than in balmy San Diego.  This
makes a huge difference in growth and blooming of
Jacaranda, Chorisia, Bauhinia, Erythrina, etc., and
other subtropical trees that prefer it warmer year
round.  

You just will not see a thriving Jacaranda, let alone
a large blooming tree in Sunset zone 17/USDA zone 9
conditions where subject to strong onshore winds right
near the coast line, unless well protected by
buildings or shelter of other trees which give it wind
protection.  As another example, Jacaranda is planted
in Santa Cruz in the downtown area, but not right next
to the beach.

In Sunset zone 14 or 8/9 conditions, I wouldn't bet on
Jacaranda as a long term hardy tree, it will more
likely be a dieback to the ground tree.  I know of
several out in Danville, which can get below 25F in
normal winters, and below 20F in colder winters, and
there are no mature trees.  It is possible to get
occasional bloom on young trees in years with milder
winters, but not safe enough to count on them as a
reliable tree choice for the inland, colder climates
that regularly freeze in winter.

Bauhinia's can often be shrubby rather than single
trunked, and this can often be a result of die back to
the ground in colder winters.  The best Bauhinia's in
bloom I ever saw were in Riyadh, Saudi Arabia, where
they thrived on the heat.  I would guess that they
also do very well in Palm Springs, Phoenix and other
low subtropical desert conditions.  You just don't see
them here in the San Francisco Bay Area, although they
might just be satisfactory bloomers in warmer areas
such as San Jose or Fremont.  As to almost any of the
vining, shrubby or tree Bauhinias, planting them to
get as much heat and wind protection as possible will
greatly increase the odds of success, but I suspect
that they all will need more summer heat than we can
provide in Sunset zone 16/17 conditions, and in hotter
inland Sunset zone 14 conditions, they aren't reliably
winter hardy without protection.  Zone 15 is probably
both too cool in summer and too cold in winter as
well.

Paulownia tomentosa and P. kawakamii are beautiful
trees in bloom, but the large leaves and weak wood
also make them poor choices for windy areas, although
they are certainly hardier to cold.  Also known to be
extremely prone to selfsowing in summer rainfall
areas, and a pest in the southeast of the USA. 
Neither species is particularly drought tolerant under
SF Bay Area conditions, and prefers regular irrigation
in summer.  One of the most magnificent specimens is
at the UC Berkeley Botanic Garden, quite large and
already heavily loaded with flower buds.  This fall
onset of flower buds also makes this a poor choice in
areas that can get hard frosts before they bloom in
March.  The flower buds are much more prone to freeze
damage than the tree itself.  

For windy areas right along the northern California
coast, trees with schlerophyl type foliage are going
to be much more reliable for coastal blooms.  My top
three would probably include Metrosideros, Eucalyptus
ficifolia and Lyonothamnus.  Many of the Melaleucas
also do extremely well.  Hakea suaveolens is also
quite reliable.   We don't really have many California
native flowering trees that do well in extreme coastal
conditions, where Pines, Cypress, Wax Myrtles, some
Ceanothus and Baccharis are the usual predominant
larger woody vegetation.  Exotics such as Myoporum and
Escallonia also do very well here, and plants such as
Aloe arborescens and Echium fastuosum can become
almost tree sized right at the beach.





	
		
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